Fuel tank level monitoring system

ABSTRACT

Described herein are embodiments of a system for monitoring and detecting a level of a tank storing a material. The system may be used in making a determination of whether and/or when to provide additional material to the tank, to refill the tank partially or entirely. In some embodiments, the tank may be disposed at a premises such as a residence or commercial building and the system may be disposed in part at that premises to monitor the level of the material in the tank. In some embodiments, the material may be a fuel and the tank may be a fuel tank, to provide fuel to utilities equipment at the premises. In other embodiments, the tank may include other materials, such as other utilities materials. In some embodiments, the utilities material may be potable water.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application Ser. No. 62/277,844, titled “Fuel tank levelmonitoring system,” filed on Jan. 12, 2016, the entirety of which isincorporated herein by reference.

BACKGROUND

Premises, including residential or commercial premises, may in somecases have utilities material piped to the premises from outside thepremises, such as piped fuel or potable water. In other cases, thepremises may include tanks to store the utilities material, such as afuel tank or a potable water tank, or tank holding another material.

SUMMARY

In one embodiment, there is provided a system to determine a level offuel in a fuel tank at a premises. The apparatus comprises a pair ofelectrically isolated conductive elements suspended inside the fuel tankat a fixed distance from each another. Each of the pair of electricallyisolated conductive elements comprising a proximal end positioned abovea highest level of fuel in the fuel tank, and a distal end opposite theproximal end positioned a distance from a bottom surface of the fueltank. The apparatus further comprises an electrical circuit thatincludes the pair of electrically isolated conductive elements, the pairof electrically isolated conductive elements forming a capacitor in theelectrical circuit; and a control circuit configured to calculate, basedon capacitor response data determined by the electrical circuit, thelevel of fuel in the fuel tank.

In another embodiment, there is provided a method comprising determininga level of fuel in a tank using a pair of electrically isolatedconductive elements disposed within the tank at a fixed distance fromeach other. Determining the level of fuel in the tank comprises excitingan electrical circuit that includes the pair of electrically isolatedconductive elements acting as a capacitor, determining capacitorresponse data for the electrical circuit, and calculating, based on thecapacitor response data, the level of fuel in the fuel tank.

In a further embodiment, there is provided at least onecomputer-readable storage medium having encoded thereon executableinstructions that, when executed by at least one processor, cause the atleast one processor to carry out a method comprising determining a levelof fuel in a tank using a pair of electrically isolated conductiveelements disposed within the tank at a fixed distance from each other.Determining the level of fuel in the tank comprises exciting anelectrical circuit that includes the pair of electrically isolatedconductive elements acting as a capacitor, determining capacitorresponse data for the electrical circuit, and calculating, based on thecapacitor response data, the level of fuel in the fuel tank.

The foregoing is a non-limiting summary of the invention, which isdefined by the attached claims.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is an illustration of a system with which some embodiments mayoperate;

FIG. 2 is a flowchart of an illustrative process for dynamicallydetermining, at a premises, whether to provide fuel to a fuel tank ofthe premises;

FIGS. 3A and 3B are flowcharts for examples of processes that may beimplemented in some embodiments for communications between a fuel tankmonitor and a relay device;

FIGS. 4A and 4B are flowcharts for examples of processes that may beimplemented in some embodiments for communications between a relaydevice and a computing device associated with a vehicle;

FIG. 5 is a flowchart of an illustrative process that may be implementedin some embodiments for a device associated with a vehicle to evaluateinformation, received from a premises, relating to a fuel tank and/orutilities equipment at the premises;

FIG. 6 is a block diagram of a computing device with which someembodiments may operate; and

FIG. 7 is a schematic of an electrical circuit that may be used in someembodiments as part of determining a level of a material in a tank.

DETAILED DESCRIPTION

Described herein are embodiments of a system for monitoring anddetecting a level of a tank storing a material. The system may be usedin making a determination of whether and/or when to provide additionalmaterial to the tank, to refill the tank partially or entirely.

In some embodiments, the tank may be disposed at a premises such as aresidence or commercial building and the system may be disposed in partat that premises to monitor the level of the material in the tank. Insome embodiments, the material may be a fuel and the tank may be a fueltank, to provide fuel to utilities equipment at the premises. In otherembodiments, the tank may include other materials, such as otherutilities materials. In some embodiments, the utilities material may bepotable water.

The system may additionally be disposed in part in a vehicle associatedwith a provider of the material, such as a fuel provider (e.g., fueldelivery company) in the case that the material is fuel. The portion ofthe system disposed at the premises may monitor the level of material inthe tank and transmit the material level (e.g., wirelessly) from thepremises for receipt by the portion of the system disposed in thevehicle when the vehicle is disposed proximate to the premises.

Upon receipt of the material level, the portion of the system disposedin the vehicle may forward the data to cloud storage or one or moreremote computing devices.

In some such cases, the data may be used at the remote computing devicesor other devices in a scheduling process, to determine when additionalmaterial is to be provided to the tank and/or when to dispatch a vehicleto deliver additional material to the tank. Determining when to provideadditional material or dispatch a vehicle may, in some embodiments,include setting or adjusting a schedule by which material is to beperiodically or occasionally provided to the tank.

Additionally or alternatively, upon receipt of a value indicative of thematerial level at the vehicle when the vehicle is proximate to thepremises, the portion of the system disposed in the vehicle maydetermine whether a condition is met for providing additional materialto the premises, which may include communicating the material level to aremote computing device and receiving in response instructions from theremote computing device to provide additional material to the premises.If it is determined that additional material is to be provided, thesystem outputs an instruction to an operator of the vehicle (while thevehicle is proximate to the premises) that additional material is to beprovided to the premises, and/or stores information indicating thatadditional material is to be provided. In some embodiments, the vehiclemay hold a reservoir of the material such that the vehicle provides thematerial to the premises when the condition is met. In such embodiments,the system may instruct the operator while the vehicle is proximate tothe premises that additional material is to be provided. Following theinstruction, the operator may provide the material to the tank to refillthe tank in part or in whole. In some embodiments, therefore, thevehicle may be disposed proximate to the premises from a time when thevalue indicative of the material level is received, through the systemmaking a determination of whether additional material is to be providedto the tank, and through the additional material being provided to thetank. This may be advantageous in some embodiments as the vehicle maynot have to visit the premises twice, once to receive the fuel level andagain to provide the additional material.

Accordingly, in some embodiments, the system may provide for a dynamicdetermination to be made of whether to refill a tank of a premises witha material, while a vehicle having a reservoir of the material isproximate to the premises. In some embodiments in which communicationsbetween components of the system are performed wirelessly, the systemmay make the determination while the vehicle is driving by the premisesalong a route to different premises, and may permit a determination tobe made without the vehicle stopping or slowing for the determination.This may advantageously enable the vehicle to stop only if adetermination to provide additional material is made, and thus enablethe vehicle to continue without stopping (or, in some embodiments,without slowing) if a determination is made that additional materialshould not be provided.

The inventors have recognized and appreciated various disadvantages ofexisting systems for monitoring fuel tank levels for residences.Existing systems transmit fuel level information remote from theresidence using an existing Internet connection of the residence orusing a wireless wide area network (WWAN) connection, such as a cellularnetwork connection. The destination of these transmissions aremonitoring services that track the fuel tank levels and make remotedeterminations of whether to send a vehicle to the premises specificallyto refuel the tank. The inventors have recognized and appreciated thatthese systems are disadvantageous because they are not technically oreconomically feasible in some circumstances. For example, someresidences do not have existing Internet connections, or may bepart-time residences that do not have Internet connections during somemonths that the fuel tank should be monitored (e.g., a summer home maynot have an Internet connection during winter months when the fuel tankis needed for heating the home). As another example, some residences maybe disposed at, or some fuel tanks may be disposed within premises(e.g., in basements) at, locations where a WWAN connection cannot bereliably made. These technical limitations prevent these existingsystems from being used in some scenarios. There are additional economiclimitations, in that the systems that use Internet connections or WWANcombined with remote monitoring have ongoing infrastructure costs thatincrease the expense of operating such systems. Operators of thesesystems typically recoup these costs through annual fees that arecharged directly to the residence owner or to a fuel delivery companythat must absorb or pass on those fees.

The inventors have recognized and appreciated the advantages of systemsthat, rather than relying on existing Internet connections or long-rangewireless connections to specialized remote monitors, operate in alocalized area specific to a premises being monitored. For example, ashort-to-mid range wireless transmission having a range similar todimensions of the residence, or up to 1 mile, may enable transmission toa vehicle proximate to the residence that is adapted to evaluate thetank level information and make a determination of whether additionalmaterial should be supplied to the tank. The determination may be madein the vehicle while the vehicle is traveling between different premiseson a route that the vehicle would follow to make deliveries, such asroutes that vehicles make when monitoring systems are not used. Thedetermination may be made while the vehicle is moving proximate to thepremises, while traveling on the route, such that the vehicle may notneed to stop or slow based on the determination. The vehicle may, insome embodiments, additionally be adapted to provide the material to thetank. In this way, existing equipment for making deliveries of materialto premises may be used to perform monitoring, rather than specialized,remotely-located equipment. Such a system that uses existing equipmentin a substantially similar manner as the equipment was already beingused (e.g., existing vehicles traveling between premises, as thevehicles were previously used) may reduce costs as compared to priorsolutions, in addition to overcoming the technical limitations discussedabove.

Examples of a system for monitoring levels of a material in tanks atpremises, and in some cases making determinations proximate to thepremises of whether to supply additional material, are discussed indetail below with respect to FIGS. 1-6. In the examples below, thematerial in the tanks is fuel. The fuel may be heating oil, propane,diesel, or any other type of fuel, including any suitable type of liquidfuel that may be used at a residential or commercial building. It shouldbe appreciated that embodiments are not limited to operating with anyparticular type of fuel. It should be further appreciated thatembodiments are not limited to operating with a material that is fuel,and instead may operate with any material that is stored in a tank at apremises for use at that premises, including use by utilities equipmentat the premises that provides utilities services to the premises.Utilities services may include electricity services, heating services,water services (including supplying potable water from a tank, filteringwater, heating water, cooling water, providing irrigation), and/orsewage/septic services. Embodiments may be used with any material thatmay be stored in a tank for such utilities services, such as anymaterial that may be consumed by utilities equipment at a premises. Forexample, in some embodiments, potable water tanks at premises may bemonitored using techniques described herein.

FIG. 1 illustrates an example monitoring and delivery system 100 withwhich some embodiments may operate. System 100 includes a premises 102that includes a fuel tank 104 to hold fuel (e.g., heating oil, propane,etc.) to be supplied to utilities equipment at the premises to provide,for example, heat and hot water to the premises. Premises 102 isillustrated in FIG. 1 as a residence but may be any suitable residentialand/or commercial building or other building that includes a fuel tank104 to supply fuel to utilities equipment at the premises. For ease ofillustration, premises 102 is illustrated with one tank, but thoseskilled in the art will understand that multiple tanks may be includedat a premises.

FIG. 1 additionally shows components of a monitoring and delivery system100 that are disposed at the premises 102, including a tank monitor 106and a relay 108. While monitor 106 and relay 108 are described andillustrated as separate devices, it should be appreciated (as discussedin more detail below) that in some embodiments some or all of thecomponents and/or functionality of monitor 106 and relay 108 may bearranged in a single integrated device, such that the integrated devicemay monitor a fuel tank and communicate directly to a receiver proximateto the premises 102 without communicating via a separate device (e.g., arelay 108).

Tank monitor 106 may be adapted to determine a level of fuel in the fueltank 104. The “level” of fuel in the tank 104 may be any suitable valueindicative of an amount of fuel in the tank, such as a value indicatinga volume of fuel in the tank, a current height of the fuel in the tank,or other value. In some embodiments, the monitor 106 may be anultrasonic monitor that is attached to an exterior of the tank 104 anduses ultrasound waves to detect a level of fuel in the tank 104. Asanother example, the monitor 106 may additionally or alternatively be asliding resistance monitor that includes a float disposed in the tankthat floats on top of the fuel and is attached to a resistance sensorsuch that as the float changes position in the tank (dependent on theamount of fuel in the tank), the resistance detected by the sensorchanges. The monitor may additionally or alternatively be a pressureswitch monitor that measures a weight of the tank on a transducer, whichmay vary as the level of fuel in the tank varies. The monitor 106 mayadditionally or alternatively be a pressure switch monitor that measuresthe air pressure in a vertically-oriented, air-filled tube that projectsdown into the tank 104 and extends to the near-bottom of the tank 104,such that the pressure in the tube changes proportionally with the levelof the fuel in the tank. The ultrasonic monitor, sliding resistancemonitor, and pressure switch monitor are conventionally-availabledevices that will be understood by those skilled in the art, and as suchwill not be discussed in detail herein.

The monitor 106 may additionally or alternatively comprise a device thatdetermines the level of material in the tank 104 by determiningcapacitance of a capacitive sensor in the tank and using the measuredcapacitance as an indicator of the level of material in the tank. Insome embodiments, the capacitive sensor can comprise a probe whichincludes a pair of equally spaced, isolated conductors within the tank.Each of the isolated conductors in the tank can, for example, comprise acapacitive plate. A capacitive plate may be comprised of conductivematerials such as aluminum, tantalum, silver, or other suitablematerials,

Properties that affect capacitance between the plates include area ofeach plate, space between the plates, and the dielectric strength ofmaterial between the plates. Given that the area of each plate and spacebetween the plates remains substantially unchanged while dielectricstrength of the material between the plates changes, the dielectricstrength can be used to measure capacitance. In some embodiments, theprobe may be immersed in the material in the tank 104. In a fuel tank,depending on the level of fuel, the probe may be immersed eitherentirely in fuel or in a combination of fuel and air. Therefore, thematerial between the capacitive plates may comprise either fuel or acombination of fuel and air. In some cases, the dielectric strength offuel in the tank 104 can be in a range of 10 to 15 mV/m and dielectricstrength of air can be approximately 3 mV/m. The dielectric strengths offuel and air may be sufficiently different that a ratio of fuel and airin the fuel tank can affect the dielectric strength of the materialbetween the capacitive plates, and thus affect capacitance between theplates.

In some embodiments, the monitor 106 may use this relation between thedielectric strength to infer the ratio of fuel and air in the fuel tankand determine a level of fuel in the fuel tank. Since the space betweenthe plates and the area of the plates can be held substantially constantand the dielectric constant of fuel and air are both substantiallyconstant values, changes in the capacitance of the capacitor within thefuel tank are influenced exclusively by the fuel to air ratio. More fueland less air may result in a higher capacitance whereas less fuel andmore air may result in a lower value capacitance. In embodiments wherethe tanks hold other materials, similar relationships between dielectricstrengths of those materials and air may be used. For example, when thetank 104 is full, the capacitance between the conductors can beestablished entirely by a dielectric strength of the material. If thetank 104 is less than full, the capacitance between the conductors canbe established by a dielectric strength based on a combination ofmaterial remaining in the tank 104 and air in a void portion of the tank104.

In one embodiment, the capacitive sensor may include an electricalcircuit to measure the capacitance. The electrical circuit can, forexample, comprise the conductors (which will be used to measure thecapacitance, as described above) and a resistor forming an RC circuit.When this type of circuit is excited with a voltage, it yields a timeresponse that corresponds to a time constant equivalent to a product ofresistance of the resistor and capacitance of the capacitor. Theresistor may have a known resistance value. The electrical circuit mayexcite the conductors and resistor, and measure the time constant. Thecapacitance may then be derived using the known resistance value and thetime constant. Different fuel levels result in different capacitancevalues that result in different time responses from the RC circuit.Exciting the circuit with a voltage and then measuring the time responsecan provide a time measurement that is proportional with the capacitanceC and, consequently, with the fuel oil to air ratio. The time responsecan be measured using, for example, a microcontroller or other device.

One example embodiment of the electrical circuit is shown in FIG. 7. Theelectrical circuit 700 can be formed by connecting the capacitor 704 anda resistor 702 of known resistance value to an NE555 timer chip or otherequivalent device. The capacitor can be connected to a threshold input708 of the NE555 timer chip 706 and the resistor can be connected to thethreshold input 708 and a discharge input 710 of the NE555 timer chip706. The monitor 106 may activate a trigger of the NE555 chip 706 totrigger an excitation signal. The electrical circuit can be used tomeasure the time constant for the capacitor response to the excitationsignal, and the monitor 106 can calculate the capacitance using theknown resistance 702 and the measured time response. For example, themonitor 106 can activate the trigger input pulse of the NE555 timer chipto start charging the capacitor 704 through the resistor 702. This inturn activates a monostable output of the NE555 timer chip which remainsactive for a time, T_(output), that may be equivalent to the following:

T _(output)=1.1 * Resistance * Capacitance

By measuring T_(output), the monitor 106 can calculate the capacitanceusing the known resistance from the formula above.

Circuits used in level measurement applications to determine thecapacitance between the plates typically utilize radio frequencies thatare altered by the capacitance of the probe. However, these circuitstend to be expensive and require higher power levels than are availablein a low power battery operated fuel level sensor. The inventorsrecognized and appreciated that electrical circuits described in someembodiments herein provide lower cost and low power methods of measuringcapacitance.

In some embodiments that measure the capacitance using an electricalcircuit as discussed above, the monitor 106 may be calibrated withmeasurements regarding tank level. In some such cases, the monitor 106may be calibrated prior to installation, or including calibrated priorto sale or distribution, such as by being calibrated at a factory orvendor. Calibration may include establishing multiple references forcapacitance values associated with levels of material in the tank 104.The references can include capacitance values for when the tank 104 isfull and when the tank 104 is empty. For example, an RC circuit such asthe one described above can be calibrated to establish a time responseof the circuit when the tanks is full, τ_(full), and a time response forwhen the tank is empty, τ_(empty). A measured time response, Σ_(m), canbe used to measure a ratio that is a measure of a current fuel or othermaterial height in the tank relative to a maximum fuel height (themaximum corresponding to a full tank) using the following equation:

${{Measured}\mspace{14mu} {Relative}\mspace{14mu} {Fuel}\mspace{14mu} {Height}\mspace{14mu} \%} = {1 - \left( \frac{\tau_{full} - \tau_{m}}{\tau_{full} - \tau_{empty}} \right)}$

This ratio value may further be used to calculate an actual volume offuel or other material in the tank:

Measured Volume=(Measured Relative Fuel Height %) * (Tank Full Capacity)

This calibration can, for example, be executed for an electrical circuitformed using a NE555 timer chip such as the one described above. In thecase of an NE555 circuit, the calibration may comprise measuring aT_(output) for a full tank and an empty tank. The monitor 106 values canthen use the calibration values along with a measured response time ofthe circuit when it is deployed to calculate relative fuel height andvolume using the formulas above.

In certain embodiments, the monitor 106 may be further configured withtank characteristics that may be used to determine material level in thetank 104. For example, in some cases, the tank 104 may have uniformhorizontal cross-sections. For this type of tank, the physical depth ofthe tank 104 may be required to determine material level. In othercases, the tank 104 may have non-uniform horizontal cross-sections. Forthis type of tank, the monitor 106 may use geometry of a region of thetank 104 to determine material level. The calibration may comprise ofdetermining multiple references for tank volumes and associatedcapacitance values. The references may include volumes and associatedcapacitance values for when the tank is full and when the tank is emptyas described in an example embodiment above. In some embodiments, themonitor 106 may be further calibrated with this information regardingthe tank characteristics at installation time, such as when atechnician, owner of the premises, or other user is configuring themonitor 106 to monitor the level of fuel in the tank 104. The tankcharacteristics or other configuration and calibration information maybe input via any suitable interface, including an interface integratedinto the monitor 106 or an interface connected wired and/or wireles slyto the monitor 106. For example, in some embodiments, the monitor 106may be configured to wirelessly communicate with a computing device,such as a mobile computing device like a smart phone or tablet computer,during a configuration phase of installation. During such aconfiguration, tank characteristic, calibration, or other informationmay be input by a user to the computing device and communicated to themonitor 106.

To determine a level of fuel in the tank 104, the monitor 106 mayadditionally or alternatively use a sensing device that measures aphysical property that is correlated with the quantity of the materialconsumed over time. In the case of a fuel tank, the monitor 106 may usedata indicating fuel consumption in conjunction with one or moretime-stamped calibration levels for the tank 104 and subsequent,time-stamped refill indications for the tank 104, to determine thecurrent level of the tank 104 at any time. The time-stamped refillindications may correspond to information received from a deviceproximate to the premises (e.g., disposed in a vehicle) or input to auser interface of the monitor 106 or another device connected wiredand/or wirelessly to the monitor 106, indicating that the tank 104 hasbeen filled to capacity. The time-stamped calibration levels maysimilarly be input to the monitor 106 via any suitable messages orinterface, and may include information indicating an amount of fuel inthe tank 104 or a level of the tank 104, as well as sensor readings tobe used by the monitor 106.

In such embodiments, to determine the level of material in the tank 104when the material is fuel, the monitor 106 may measure one or more ofthe following properties of a furnace, boiler, or other utilitiesequipment at the premises: the fuel burner motor voltage or current, thefuel burner flame detector, the fuel burner motor or blower vibration,the fuel burner blower air flow, absolute temperature and/or temperaturerate of change. Each of these properties can provide an indication of afuel burner run time. The monitor 106 may use the fuel burner run timein conjunction with knowledge of fuel burner consumption rate todetermine an amount of fuel consumed by the fuel burner.

In some such embodiments, the monitor 106 may use temperature todetermine fuel burner run time. Absolute temperature and temperaturerate of change can be measured at several locations on theburner/furnace system. Temperature rate of change on the exhaust pipe orstack can closely correlate with fuel consumption. It is appreciatedthat measuring temperature is an inexpensive means of determining fuelburner run time. The monitor 106 can, for example, collect temperaturedata direction from a temperature sensor using an I²C interface or byconverting analog sensor output to digital data using a microcontroller.Alternative electronic voltage or current monitoring techniques requiredirect connections to high voltage AC that then require installation bya certified electrician or HVAC technician. Products that have highvoltage AC circuits or connections also require product safety testingand certification. All of these requirements adversely affect productand/or installation cost. Temperature sensing may not require specialcertification of the installer or the product itself.

In one example embodiment, the monitor 106 may measure temperature of anexterior surface of a flue vent of a fuel burner. The flue vent on manyfuel burners is easily accessible for sensor installation, has arelatively fast thermal response time, and provides accurate andreliable correlation with the burner run time and fuel consumption. Thespecific location of the temperature sensor on the flue vent is notcritical because of the large temperature differential between the hotexhaust gasses inside the flue vent and the ambient temperature outsidethe pipe. Further, temperature is substantially uniform across the fluevent. In some embodiments, the flue vent is only a few feet in lengthand locating the temperature sensor anywhere on its surface isacceptable.

When the fuel burner state changes, the flue vent temperature maychange. At start up, for example, the flue vent surface temperature maystart to increase within a period of time. The short period of time canbe, for example, in a range of 4 to 5 seconds. The flue vent temperaturemay continue to increase at a decreasing rate of change until thetemperature reaches steady state, per the thermodynamic principles. Whenthe burner shuts off, the stack pipe surface temperature may start todecrease within a short period of time. The period of time can be, forexample, in a range of 4 to 5 seconds. The flue vent temperature maycontinue to decrease at a decreasing rate of change until it achievessteady state, per the thermodynamic principles. In some embodiments, themonitor 106 may add a constant heat-up and/or cool down constant valueto the measured time during which the stack pipe temperature is changingindependent of ambient temperature change to achieve a required burneron-time measurement accuracy. Very short burner run times, such as timesless than 4 seconds, are uncommon. For example, a very short burner runtime following shut-off of one zone and start-up of another zone, may beprohibited by a hysteresis performed by the fuel burner control unit.Even if very short on or off cycles are possible, burner time onmeasurement errors from those cases may be negligible. For typicalburner consumption rates, each start-up and shut down would represent anerror of 0.036 ounces total fuel consumption error and 0.03% per secondof consumption rate error.

In some embodiments, the monitor 106 may sample the flue venttemperature frequently enough to detect changes in conditions indicatingburner run time. The monitor 106 may sample the temperature at afrequency of at least twice the rate of change of the flue vent surfacetemperature reaction to burner state changes. For example, the monitor106 may sample temperature values at a rate of 2 Hz to ensure thatchanges may be detected for a fuel burner temperature changes that takes4 or more seconds to be reflected in the temperature of the flue ventsurface. The monitor 106 may perform further data processing activitiesto ensure accurate temperature measurements. The monitor 106 may, forexample, average or smooth collected temperature data to filter noise.The monitor 106 may then use processed data to detect changes intemperature to measure burner on time. In one example, the monitor 106can detect reversal of slope in the temperature data to determine theburner turning on or off. The monitor 106 may then use timestamps of onand off detections to calculate burner run time.

In some embodiments, the monitor 106 may use the burner on time withfuel consumption rate, initial fuel level, and amount of fuel added todetermine a fuel level in the fuel tank 104. The fuel consumption ratemay, for example, be determined by a burner nozzle size. A larger burnernozzle size may correlate with a higher consumption rate. The fuelconsumption rate may also be a constant value associated with a burnertype. In one example, the current level in the tank 104 may becalculated over time according to the following formula:

Current Tank Level=Initial Level+Fuel Added−Fuel Consumed

where

Fuel Consumed=Burner On Time * Fuel Consumption Rate

Burner on time may be calculated in a manner described in examplesabove, or using other methods. Other sensors, parts, and combinationsthereof may be used to determine a burner on time. Note that anydiscussion about the flue vent can also refer to a single wall thicknessvent pipe, stack, flue pipe, or exhaust pipe of the fuel burner.

It should be appreciated that while examples of monitors have beengiven, embodiments are not limited to a particular type of monitor thatmay be used to determine a level of fuel in the tank 104 and anysuitable device or equipment for determining a level of fuel in the tank104 may be used.

In some embodiments, in addition to determining tank level, the monitor106 may be adapted to collect information on an operating state ofutilities equipment at the premises, such as the utilities equipmentsupplied by the fuel tank 104. The operating state information mayindicate whether the utilities equipment is functioning properly or isin need of maintenance/repair. This may be helpful to collect because,in some cases such as summer homes for which fuel is being supplied forwinter heating, premises may be unoccupied while the monitoring systemis in use and collecting information on operating state may aid inpreventing or mitigating an emergency at the premises.

The type of information that indicates an operating state of utilitiesequipment may vary based on the type of utilities equipment that ismonitored. In some embodiments, the monitor 106 may collect thisinformation in the form of environmental information indicating acondition of an environment of the monitor 106. For example, temperatureinformation indicating an ambient air temperature of an area in whichthe monitor 106 is disposed may be collected. The air temperature mayindicate whether heating utilities equipment is properly functioningbased on whether the air temperature is below a temperature that wouldbe considered appropriate for the premises (e.g., a temperature near orbelow freezing), which may be a per-premises value or a default valuefor all premises. Additionally or alternatively, a level of ambientcarbon monoxide may be detected, which may indicate a failure in heatingequipment. Additionally or alternatively, humidity information may becollected, which may indicate a failure (e.g., a leak) in waterequipment at a premises, where the utilities equipment provides waterservice. Other environmental conditions for other types of utilitiesequipment may additionally or alternatively be detected, as embodimentsare not limited in this respect.

Additionally or alternatively, in embodiments in which the monitor 106detects proper functioning of the utilities equipment, the monitor 106may detect equipment-specific information, which may be provided by theequipment or by a device adapted to monitor specific equipment. Forexample, the monitor 106 may determine whether a burner lockoutcondition has occurred on heating equipment such as a furnace. Themonitor 106 may receive the information on the burner lockout by beingcommunicatively connected to the utilities equipment to detect theburner lockout, or otherwise being adapted to receive the informationfrom the utilities equipment. In some embodiments in which a burnerlockout is detected, monitor 106 may include a physically separatecomponent to interface with utilities equipment and receive informationon burner lockout conditions, and wireless transmit to another componentof the monitor 106 information indicating that a burner lockout hasoccurred.

The monitor 106 includes a wireless transmitter (or wirelesstransceiver, or other wireless communication circuit) to transmit thefuel tank level information and (in embodiments in which it iscollected) utilities equipment operating state information from themonitor 106. In the example of FIG. 1, the monitor 106 transmits theinformation to a wireless relay 108 that receives and stores theinformation to be transmitted outside the premises 102. The monitor 106may transmit the data to the relay 108 upon occurrence of a condition,and the relay 108 may continuously, periodically, or occasionally (e.g.,upon satisfaction of a condition) transmit the most-recently-receiveddata from the premises to be received by a receiver (e.g., in a vehicle)when a receiver is positioned proximate to the premises 102. Details ofhow the monitor 106 and relay 108 may communicate in embodiments aredescribed below with respect to FIGS. 3A-4B.

In the example of FIG. 1, the monitor 106 and relay 108 are physicallyseparate devices. This may be advantageous in embodiments in which thetank 104 being monitored is a fuel tank, due to safety restrictionsregarding fuel tanks and operating powers of devices disposed near fueltanks. Specifically, in some embodiments the relay 108 may be a devicewith relatively high power requirements, because in these embodimentsthe relay 108 may transmit data at a high frequency (i.e., often) awayfrom the premises to a receiver (e.g., a vehicle) disposed proximate tothe premises. Because many transmissions may be sent, and depending onpower requirements of the protocol used for the transmission, poweringthe transmission of the data to a vehicle disposed proximate to thepremises may require a large power reserve. The large power reserve maybe provided by grid power or by a battery that may be relatively highcapacity to reduce or avoid undesirable frequent battery changes.Positioning a device powered by grid power or a large-capacity batterynear a fuel tank may be a fire/explosion risk and may be prohibited bybuilding codes in some cases. To overcome these safety restrictions, insome such embodiments a physically separate monitor 106 and relay 108are provided. The monitor 106 may transmit less frequently than therelay 108 (e.g., only on occurrence of a condition) and transmit only ashort distance to the relay 108, within the premises 102. Accordingly,in these embodiments, the monitor 106 may not require a large amount ofpower, and a lower-capacity battery may be used than would be requiredif the relay 108 were incorporated with the monitor 106. Thislower-capacity battery may not raise safety concerns regarding the fueltank.

Accordingly, in some embodiments and as shown in FIG. 1, the system 100may include a monitor 106 that collects fuel tank information (and, insome cases, utilities equipment operating state information) andtransmits it to a relay 108. The relay 108 may then transmit theinformation outside the premises to a receiver proximate to thepremises.

However, in embodiments in which fuel tank concerns may be mitigated insome manner, such as through lower-power communications or less frequentcommunications, the system 100 may not include separate devices formonitor 106 and relay 108. Instead, a single integrated device includingsome or all of the fuel tank monitoring components and/or functionalitythe monitor 106 may include some or all of the communication componentsand/or functionality of relay 108, and may monitor a fuel tank andcommunicate tank level information directly to a receiver disposedproximate to the premises. Thus, in some embodiments, some or allcomponents and/or functionality discussed herein of both the monitor 106and relay 108 may be integrated into the same device, with thesecomponents integrated, for example, in the same housing. The componentsmay include sensing components of the monitor 106 and communicationcomponents of the relay 108. In some embodiments, these components ofthe monitor 106 and relay 108, when disposed in the same integrateddevice, may be in electrical communication with each other. For example,a hardwired circuit may be used to electrically connect components ofthe monitor 106 to components of the relay 108 within the integrateddevice. In some cases of a hardwired circuit, the components may beconnected via a printed circuit board (PCB), and a communicationprotocol such as SPI or I²C may be used for communication between thecomponents. In some such cases of an integrated device, as discussedabove with respect to monitor 106, sensing components of the integrateddevice may be configured to collect information on an operating state ofutilities equipment at the premises, in addition to or as an alternativeto sensing a tank 104 directly. In some embodiments that include anintegrated device, the device may be configured to use power levelssufficiently low to mitigate or eliminate safety concerns mentionedabove. Power levels that are low enough to overcome safety concerns maybe determined according to local safety regulations or other standards.The power may be provided from one or more batteries and/or by gridpower, and in some cases may be supplied by the grid via a powertransformer to convert a high power from the grid into a lower powervalue that addresses safety concerns.

Embodiments are described herein in which a system 100 includes amonitor 106 and a relay 108 as physically separate devices. It should beappreciated that, unless stated otherwise, functionality describedherein as performed by either monitor 106 or relay 108 may beimplemented by an integrated device in some embodiments, including bybeing performed by components included in an integrated device that aredescribed herein as implemented in either monitor 106 or relay 108.

In the example of FIG. 1 that includes different devices, the monitor106 and relay 108 may communicate using a communication protocol thathas a range similar to or less than dimensions of standard residentialpremises, such as a range less than 300 feet, or a range less than 150feet, or a range less than 75 feet. As used herein, a “short range”protocol is a protocol having such a range less than 300 feet, or lessthan 150 feet, or less than 75 feet, as opposed to a “long range”protocol such as a Wireless Wide Area Network (WWAN) protocol or aWireless Municipal Area Network (WMAN) protocol that have ranges greaterthan 300 feet. Short range protocols that may be used in embodimentsinclude Wireless Local Area Network (WLAN) protocols and WirelessPersonal Area Network (WPAN) protocols, including IEEE 802.11,Bluetooth®, and ZigBee® protocols. In some embodiments, the monitor 106and relay 108 may communicate using a different protocol, such as onehaving a shorter range, than the relay 108 uses to communicate with areceiver disposed adjacent to the premises. For example, in someembodiments the monitor 106 may communicate to the relay 108 using aWPAN protocol such as ZigBee and the relay 108 may communicate to thereceiver using a WLAN protocol such as IEEE 802.11. In otherembodiments, however, the same protocol may be used. For example, insome embodiments, a ZigBee® protocol may be used for communications bythe monitor 106 and relay 108. In embodiments that include an integrateddevice, the integrated device may communicate using a WLAN protocol suchas IEEE 802.11. Embodiments are not limited to operating with anyparticular protocol or type of protocol.

While wireless transmissions have been described between the monitor 106and relay 108, it should be appreciated that in some embodiments wiredcommunication could be used. Further, while the monitor 106 wasdescribed as collecting utilities equipment operating state informationand transmitting it to the relay 108, in some embodiments in whichutilities equipment operating state information is collected, the relay108 may collect the state information itself or from another device,separate from the monitor 106, that is adapted to collect the stateinformation.

Examples of components of the system 110 disposed at the premises 102have been described. As illustrated in FIG. 1, in some cases there maybe multiple premises, such as premises co-located in an area or along aroute being serviced by a fuel delivery company or other provider ofmaterial. Each of the other premises 102B, 102C, etc. may be arrangedsimilarly to the manner shown and discussed above with respect topremises 102. As should be appreciated from the discussion above andbelow, in some embodiments a receiver in a vehicle may travel betweenthe premises 102, premises 102B, premises 102C, etc. along a route toreceive and evaluate fuel tank level information (and other information,in some embodiments). In some embodiments, the vehicle may also beconfigured to evaluate fuel tank level information and to determine,when proximate to a premises, whether fuel is to be provided to thatpremises. It should be appreciated, however, that embodiments are notlimited to making a determination of whether to provide fuel whileproximate to the premises.

Thus, the relay 108 may transmit the fuel tank level information and/orthe utilities equipment operating state information from the premises102 to a receiver 110 disposed proximate to the premises 102. As shouldbe appreciated from the foregoing, where the premises has an existingcommunication network, such as a WLAN for the premises, or where thepremises is accessible via a WWAN the extends over the premises, theexisting communication network may not be used to transmit the fuel tanklevel information and/or utilities equipment operating stateinformation. In some embodiments, the information may be transmitted viaan ad hoc network formed by the relay 108 and the receiver 110 while thereceiver 110 is proximate to the premises.

In some embodiments, the information may be transmitted by the relay 108along with information identifying the premises 102, such as addressinformation, owner identification information, account information, anidentifier for the relay 108, and/or other information. The identifyinginformation may have been stored in the relay 108 when the relay 108 isinstalled in the premises 102. The fuel tank level information that istransmitted may be in a similar form as it is produced by and/orreceived from the monitor 106, or may be processed by the relay 108 andbe in a different form that is indicative of a fuel tank level. Forexample, in a case that premises 102 includes multiple tanks 104 forwhich a monitor 106 transmits data to relay 108, the fuel tank levelinformation for each tank may be transmitted to the receiver 110, suchas with an identifier for each tank. Alternatively, the relay 108 maydetermine, from tank level information received for multiple tanks frommultiple monitors 106, a fill level relative to total capacity andtransmit that value.

As used herein, “proximate” to the premises 102 includes within range ofthe communication protocol by which the relay 108 transmits the data. Inembodiments in which a short range protocol is used that has a rangewithin 300 feet or within 150 feet or within 75 feet, “proximate” to thepremises may include being within the 300 feet or within the 150 feet orwithin the 75 feet. In embodiments in which a mid-range protocol is usedthat has a range within 1 to 2 miles, “proximate” to the premises mayinclude being within the 1 to 2 miles.

In some embodiments, the relay 108 device may transmit the fuel tankinformation together with utilities equipment operating stateinformation, from the premises 102 to a receiver 110 disposed proximateto the premises 102.

In the example of FIG. 1, the receiver 110 is a fuel delivery truck thatincludes a fuel reservoir and equipment, including valves, pumps, hoses,etc., to transfer fuel from the reservoir to the fuel tank. The receiver110 may additionally include at least one computing device 112 toreceive the data from the relay 108 and evaluate the received data. Asmentioned above, in some embodiments the computing device 112 maydetermine whether fuel should be delivered to the fuel tank 104 whilethe receiver 110 is proximate to the premises 102. Specifically, thecomputing device 112 may execute a refuel determination facility thatreceives and evaluates the information and outputs an instruction to anoperator of the vehicle 110 to deliver or not deliver fuel to the tank104. The evaluation performed by the facility may include informationspecific to the premises 102. Examples of ways in which the evaluationmay be conducted are described below in connection with FIG. 5.

The refuel determination facility executing on the computing device 112may in some embodiments communicate with a computing device 114, as partof or as an alternative to evaluating the fuel tank information locallyas part of making a decision of whether to refuel. In some cases, thedevice 112 may communicate with the device 114 before the vehicle 110travels a route to one or more premises to receive information abouteach of the premises. Examples of such information are discussed belowwith respect to FIG. 5. Additionally or alternatively, the device 112may communicate with the device 114 to inform the device 114 when adelivery is made to a premises 102, and/or an amount of fuel (or othermaterial) delivered to the premises 102. In some embodiments, the device114 or an operator of the device 114 may adjust a scheduled route of thevehicle 110 if many deliveries are made and a fuel reservoir of thevehicle 110 may be running low, or if very few or no deliveries are madealong an initial portion of a route and a determination is made by thedevice 114 or operator that it is likely that no more deliveries will bemade (e.g., if weather has been warm recently, and an initial portion ofroute confirms that little fuel has been consumed by premises since alast evaluation, the route may be prematurely ended).

Additionally or alternatively, in some embodiments, the device 112 maynot include any customer data or other information that may be used toevaluate received data from relay 108. Such other information may beimportant, for example, in determining whether a fuel level of a tank104 at a particular premises 102 is below a refueling threshold specificto that premises 102. In such a case, the relay 108 may transmit anidentifier for the relay 108 and/or monitor 106. The computing device112 may send the received data, including the identifier(s), to theremote computing device 114. The computing device 114 may use theidentifier(s) to determine the premises to which the receivedinformation corresponds. In addition, where fuel tank informationreceived from the relay 108 includes sensor values or other informationindicative of a fuel level, rather than a fuel level, the computingdevice 114 may process received fuel tank information to determine afuel level in the tank 104. The computing device 104 may further make adetermination of whether fuel should be delivered to the fuel tank 104,which may be done in the manner described below in connection with FIG.5.

Upon determination by the remote computing device 114 to make a fueldelivery to the fuel tank 104, that determination may be sent from theremote computing device 114 to the vehicle-based computing device 112 toinform the vehicle operator. Though, it should be appreciated that insome embodiments, a determination may not be made of whether to refuel atank 104, while the vehicle is proximate to the premises 102. In suchother embodiments, the device 114 may store fuel tank information foruse in scheduling a refueling of the tank 104, such as confirming oradjusting a scheduled refueling of the tank 104 at some point in thefuture. For example, if the device 114 determines based on tank levelsdetermined over a period of time that the premises 102 are consumingfuel at a lower rate than predicted, the device 114 may schedule arefueling to be at a later date/time than otherwise.

In some embodiments in which the device 112 receives utilities equipmentoperating state information from the relay 108, the device 112 may alsocommunicate the utilities equipment operating state information to thedevice 114. In such a case, if an error or potential error in utilitiesequipment is indicated by the information, or an analysis of theinformation reveals that there may be an error, the device 114 maynotify an administrator of the fuel tank monitoring system of anydetected error. The notification may be made by displaying a message viaa user interface, and/or by sending a text (SMS) message and/or email orplacing a phone call to an administrator of the system and/or to a userassociated with the premises (e.g., an owner of the premises or aproperty manager for the premises). In the case of a phone call, atext-to-speech message may be relayed or a previously-recorded messagemay be played back over the phone call. The message may include anysuitable content relating to the operating state of the utilitiesequipment.

Operations performed by the device 114 may be performed by any suitablesoftware facility (or facilities) executing on the device 114.

The computing device 114 may include a data store 114A of information,such as information on each of the premises that are to be evaluated.Examples of ways in which this information may be used are describedbelow in connection with FIG. 5.

While in the example of FIG. 1, the vehicle 110 includes a fuelreservoir and is adapted to perform deliveries, embodiments are not solimited. For example, in some embodiments, a receiver 110 may be areceiver that is not able to deliver fuel but instead may be a small car(potentially more fuel-efficient than a fuel tanker) that drives a routeto identify which premises should be refilled by a fuel tanker, and thefuel tanker may subsequently visit each of the identified premises. Insuch embodiments, the refuel determination facility may storeinformation identifying each of the premises for which fuel deliveriesshould be made, such as by storing the information locally on the device112 and/or by communicating to the device 114.

While the example of FIG. 1 described the relay 108 communicating, insome embodiments, utilities equipment operating state information to thedevice 112 in the vehicle 110 for evaluation by the refuel determinationfacility executing on the device 112 (as discussed in greater detailbelow) and/or on the device 114, it should be appreciated thatembodiments are not limited to evaluating the utilities equipmentoperating state information only on the device 112. In some embodiments,for example, the monitor 106 may be additionally or alternativelyconfigured to perform the analysis described herein of the utilitiesequipment operating state information to determine whether the utilitiesequipment is in an improper state, such as malfunctioning. In some suchembodiments, if the monitor 106 determines from the evaluation that theutilities equipment is in an improper state, the relay 108 may transmita notification of the improper state. For example, the relay 108 mayinclude a short-range wireless communication circuit to transmit toreceivers (e.g., device 112) proximate to the premises, and mayadditionally include a long-range wireless communication circuit totransmit, such as via a WWAN (e.g., cellular network) or WMAN, toreceivers remote from the premises a notification of the improper state.For example, in response to determining the improper state, the relay108 may transmit via the long-range wireless communication circuit anotification of the improper state and/or a potential emergency at thepremises. The relay 108 may additionally transmit a notification of theimproper state along with fuel tank level information and otherinformation, as described herein.

Examples of operations of and communications between components of thesystem 100 have been described above. For ease of understanding, FIG. 2illustrates a flowchart of a process 200 that may be implemented by asystem 100 to monitor fuel tank levels and make a dynamic determination,at a premises, of whether a fuel tank at the premises is to be refilled.In addition, FIGS. 3A-5 illustrate in more detail examples of operationsthat may be performed by components of the system 100. It should beappreciated, however, that embodiments are not limited to operating asdescribed below with respect to any of FIGS. 2-5, as other embodimentsare possible.

The process 200 of FIG. 2 begins in block 202, in which a monitorattached to a fuel tank detects a level of fuel in the tank andtransmits the fuel tank level to a relay. As discussed briefly above andin further detail below, the monitor may detect and transmit the fueltank level upon satisfaction of a condition. In block 204, the relaydevice transmits the fuel tank level information and informationidentifying the premises continuously, or at regular intervals of shortduration (e.g., every 1 second, every 10 seconds, etc.). The fuel tanklevel information may include information on the level of fuel in thetank and any other suitable information on the tank or the fuel, such asa type of the fuel in the tank and/or a capacity of the tank. Examplesof information identifying a premises are described above. The relay maytransmit the fuel tank level information and identifying informationoutside the premises, using a protocol having a range to reach a vehicledisposed proximate to the premises. In embodiments in which utilitiesequipment operating state information is detected by the monitor andtransmitted in block 202, the relay may also transmit the stateinformation in block 204.

In block 206, a refuel determination facility executing on a computingdevice disposed in a vehicle, and/or executing in whole or in part on aremote computing device, receives the fuel tank level information. Insome embodiments, the fuel tank level information may be receivedtogether with premises identifying information. In block 208, the refueldetermination facility evaluates the fuel tank level information todetermine whether a refuel condition is met. The refuel condition may beunique to the premises, and may be identified based on the premisesidentifying information received along with the fuel tank levelinformation. If the refuel determination facility determines in block208 that the refuel condition is not met, then the process 200 ends. If,however, the refuel determination facility determines that the conditionis met, the facility outputs an instruction to an operator of thevehicle to refuel the tank at the premises. Examples of ways in whichthe operations of blocks 206-210 may be performed are described ingreater detail below with respect to FIG. 5. After the instruction isoutput, the process 200 ends.

The process 200 may be repeated for each premises, with the acts ofblocks 202, 204 being executed at a premises repeatedly and the acts ofblocks 206-210 being executed by a refuel determination facility as thevehicle travels a route between premises.

FIGS. 3A and 3B illustrate examples of processes that may be implementedby a tank monitor, such as the monitor 106 of FIG. 1, to determinewhether to measure a level of fuel in a tank and whether to communicatethe tank level information to a relay. As discussed above, inembodiments that include a relay separate from a monitor, the monitormay communicate with the relay only upon satisfaction of a condition.

In the example of FIG. 3A, the condition is expiration of a time period.The process 300 of FIG. 3A begins in block 302, in which the monitordetermines whether a timer has expired. The time period of the timer maybe any suitable time period, as embodiments are not limited in thisrespect. In some embodiments, the time period may be 10 minutes, 30minutes, 1 hour, 2 hours, 6 hours, 8 hours, 12 hours, or 24 hours, orany suitable value within a range of 1 to 30 minutes, 30 to 60 minutes,or 1 hour to 24 hours. In some advantageous embodiments, the time periodmay be one hour.

If the timer has not expired, the process 300 stays in a loop, until thetimer expires. Once the timer expires, in block 304 the monitordetermines a value indicative of the fuel level in the tank, which insome cases may be a value that expressly indicates the amount of fuel inthe tank while in other embodiments may be a value that may be processedto determine the amount of fuel in the tank. The manner of determinationmay vary depending on the type of level determination the monitor isadapted to perform, examples of which are described above. In someembodiments, a value that expressly indicates an amount of fuel in thetank may be determined, such as in some embodiments in which anultrasonic sensor is used. In other embodiments, such as embodimentsthat measure a physical property of utilities equipment to determine avalue indicative of tank level or other measurement techniques are used,the monitor may produce a voltage value, capacitance value, temperaturevalue or other measurement value that may not itself expressly indicatethe tank level, but rather may be indicative of the tank level. Thatvalue produced by a sensor of the monitor may be processed by themonitor, the relay, and/or by a computing device outside the premises toproduce a value indicative of a level of fuel in the tank. As discussedabove, the value indicative of the level of fuel in the tank may be avalue indicating an amount of fuel in the tank, such as indicating avolume of fuel in the tank. In some embodiments, the monitor may beconfigured with a total volume of the tank, which the monitor may use inprocessing the voltage value or other measurement value to produce thevolume value indicative of the remaining fuel. Those skilled in the artwill understand how to configure a tank monitor to produce a volumevalue from a measurement value.

In block 306, once the value indicative of the fuel level is determinedin block 304, the value indicative of the fuel level is transmitted tothe relay. Any suitable transmission technique may be used, asembodiments are not limited in this respect. For example, in someembodiments a stateful communication may be used in which a connectionis established between the monitor and the relay, and in which the relayacknowledges when the fuel tank level is properly received. In such acase, if the relay does not acknowledge proper receipt, the monitor maycontinue transmission until the fuel tank level is properly received ora determination is made (e.g., after a number of retransmissions) thatthere is error preventing proper communication. In other embodiments, abest-effort, stateless communication protocol may be used in which thedata is transmitted by the monitor without determining whether the relayproperly received the fuel tank level information.

In some advantageous embodiments, the monitor may transmit the fuel tanklevel information to the relay using a ZigBee® protocol. It should beappreciated, however, that embodiments are not limited to using ZigBee®.

Once the fuel tank level information is transmitted in block 304, theprocess 300 returns to block 302 to determine when, following thetransmission, the time period has expired again. In this way, the fueltank level is detected and transmitted regularly, upon repeatedexpirations of the time period.

In the example of FIG. 3B, the condition is a significant change in fuellevel in a tank (or a significant change in the value detected by themonitor, in embodiments in which a value merely indicative of, and notexpressly indicating, the level of fuel in the tank is determined). Thischange in fuel level may be an increase in fuel and correspond tofilling of the tank with fuel. It may be important in some cases for therelay to be informed immediately if the fuel tank has been refilled.This may be important particularly where the time period of FIG. 3A isalso used as a condition and the time period is long (e.g., longer than1 minute or 5 minutes). For example, if the time period is one hour,then fuel tank level information held by the relay and transmitted to areceiver (e.g., fuel tank delivery truck) may be as much as one hourold. If, during that time, another fuel delivery truck visited thepremises and refilled the tank to completely full, a newly-arriving fueldelivery truck may be misinformed about the level of the tank and mayattempt to fill the tank again. This may lead to an overfilling of thetank that may result in spills that may be ecologically difficult andconcerning, or at least undesirable. Such a mistaken duplication ofdeliveries may occur due to miscommunication between two trucks for afuel delivery company, but may more commonly arise due to a mistakendelivery on the part of a fuel delivery company that does not service apremises followed by a delivery by a fuel delivery company that doesservice the premises.

Accordingly, in the example of FIG. 3B, the process 320 begins with thefuel tank monitor determining a value indicative of the fuel tank levelin block 322. The detection may be performed as discussed above inconnection with block 304 of FIG. 3A. The fuel tank monitor may detectthe fuel tank level continuously, or at an interval (e.g., any of theintervals discussed above in connection with FIG. 3A) in this example.In block 324, by comparing a current fuel tank level (or value) to aprior fuel tank level (or value), such as a level from animmediately-preceding detection or a set of multiple detections, themonitor may determine whether it has observed a sudden increase in fuellevel in the tank. The monitor may determine whether there has been asudden increase by determining whether a rate of change over time isgreater than a threshold, or whether a fuel level between successivedetections shows an increase in fuel of more than a threshold amount. Ifnot, then the process 320 returns to block 322 to detect the fuel levelcontinuously or at an interval. If, however, the monitor determines inblock 324 that there has been a sudden increase, in block 324 themonitor transmits the current fuel level to the relay. The transmissionmay be performed as discussed above in connection with block 306 of FIG.3A. Once the fuel tank level is transmitted in block 326, the process320 returns to block 322 to detect fuel tank level.

While the processes of FIGS. 3A and 3B are illustrated separately, insome embodiments both conditions may be used. For example, the process320 of FIG. 3B may be used to monitor fuel tank level continuously or ata first time interval and transmit if a sudden increase is detected, butalso to transmit the most-recently-detected (or detect again) the fueltank level upon expiration of a second time interval greater than thefirst time interval. For example, the monitor may detect the tank levelevery 5 seconds and transmit if a sudden increase is detected, and alsotransmit the tank level once per hour.

The relay 108 may be adapted to receive any data transmitted to it fromthe monitor, and may be operable to receive data at any time. Forexample, the relay may be configured to continuously listen forcommunications from the monitor and store the received data. In otherembodiments in which the monitor transmits only upon expiration of acertain time interval (e.g., embodiments in accordance with FIG. 3A),the relay may be configured with a similar time interval and may onlylisten for and receive data from the monitor at the time interval. Thismay be advantageous in some embodiments as it may decrease powerconsumption by the relay, but those skilled in the art will understandthat a relay that only receives data at certain intervals may not bebest if a system for detecting sudden increases in fuel in a tank are tobe detected, as discussed above in connection with FIG. 3B.

FIGS. 4A and 4B illustrate examples of processes that may be used by therelay to transmit data to a receiver. The data, as discussed above, mayinclude fuel tank level information and identifying information for thepremises (and, in embodiments in which it is collected and transmitted,utilities equipment operating state information). The identifyinginformation for the premises may include any suitable informationidentifying a premises, such as an address for the premises, a name ofan owner of a premises, an account number such as for a fuel deliveryaccount associated with the premises, and/or an identifier for the relayand/or monitor (or a component thereof, such as a MAC address for atransmitter of the relay) that may be used to identify the premisesbased on a relationship between the relay and the premises/account. Insome embodiments, though, as discussed above, the relay may onlytransmit the fuel tank level information (and, in some cases, theutilities equipment operating state information) together with anidentifier for the relay and/or monitor. The identifier for the relayand/or monitor may then be used by a receiver to identify the premises,as discussed above.

In some embodiments, the relay may transmit the data continuously or onexpiration of a time interval, for receipt by a vehicle that may bedriving past. In such embodiments, and where an interval is used, any ofthe exemplary time intervals discussed above in connection with FIG. 3Amay be used. Though, because it may be uncertain in some embodimentswhen a vehicle may pass by, it may be advantageous to use a brief timeinterval, such as an interval of 3 or 5 seconds or less, such as onesecond. FIG. 4A illustrates an example of such an embodiment. Theprocess 400 of FIG. 4A begins in block 402, in which the relaydetermines whether a time has expired. When the timer has expired (e.g.,every 1 second), in block 404 the relay transmits the most recentlyreceived fuel data and identifying information. The data may betransmitted in any suitable protocol, as embodiments are not limited inthis respect. For example, the data may be transmitted in accordancewith an IEEE 802.11 protocol, a ZigBee® protocol, or any other suitableWLAN or WPAN, or short-range, protocol. The message that is transmittedmay be a broadcast message that does not specify a recipient, or mayinclude an identifier for a destination/intended recipient with whichthe relay was preconfigured and with which a receiving device of thevehicle (e.g., device 112 of FIG. 1) will be configured. In someembodiments, a stateful communication may be used in which a connectionis established between the relay and the receiver, and in which thereceiver acknowledges when the data is properly received. In such acase, if the receiver does not acknowledge proper receipt, the relay maycontinue transmission until the fuel tank level is properly received ora determination is made (e.g., after a number of retransmissions) thatthere is error preventing proper communication. In other embodiments, abest-effort, stateless communication protocol may be used in which thedata is transmitted by the relay without determining whether thereceiver properly received the fuel tank level information. In theexample of FIG. 4A, a best-effort, stateless communication may be usedtogether with broadcast transmission, such that a vehicle proximate tothe premises at any time may receive (or be likely to receive) the datatransmitted by the relay.

Once the data is transmitted in block 404, the process 400 returns toblock 400 to monitor the timer and transmit again upon expiration of thetimer.

In examples described above, including the example of FIG. 4A, thecomputing device disposed in the vehicle (e.g., device 112 of FIG. 1)that receives fuel tank level data and other information from the relayis a passive device. In this way, the device merely receives data whenit is within range of a premises and a relay disposed at that premises,but does not seek out data from any particular premises. It should beappreciated, however, that embodiments are not limited in this respect.In some embodiments, a device of a vehicle, that is executing a refueldetermination facility, may be configured with information on accountsalong a route. Using location determination functionality, such as usingGPS, Assisted GPS, or another location determination system, the devicemay monitor a current position of the vehicle. When proximate to aparticular premises along the route, the device may request fuel tanklevel information for the premises by communicating with the relay atthe premises. FIG. 4B illustrates an example of a process that may beimplemented by a relay in such an embodiment.

The process 420 of FIG. 4B begins in block 422, in which the relaydetermines whether it has received, from a device of a vehicle, a probecommunication requesting tank level information from the premises withwhich the relay is associated. In some embodiments, the probecommunication for the premises may identify the premises with anidentifier contained within the probe, which may be any of the examplesof premises identifiers described above. When a probe is received, therelay may determine whether it is a probe intended for the premises orintended for another premises by evaluating the identifier and comparingit to stored identifier(s) for the premises. In other embodiments, theprobe may be broadcast, asking all recipients that are parts of a fueltank monitoring system and are customers of the fuel provider with whichthe vehicle is associated to transmit fuel tank level information.

If no probe is received, then the process returns to block 422 and therelay continues to wait for such a probe communication.

If, however, the relay has received the probe communication, in block424 the relay retrieves from a data store a fuel tank level mostrecently received from a monitor and transmits the fuel tank level (andpremises identifying information and utilities equipment operating stateinformation, if applicable) to the source of the probe. The transmissionmay be made in block 424 as discussed above in connection with block 404of FIG. 4A. Once the data is transmitted, the process 420 returns toblock 422 to wait for another probe. In embodiments like that describedin connection with FIG. 4B, in connection with block 422, the relay 108may periodically or occasionally wake up from a low power, sleep stateand “listen” for a signal periodically or occasionally sent by thevehicle-based mobile computing device 112 to determine if a compatiblelistening device is proximate to the premises. In one example, a deviceis determined compatible if information is received indicating that thedevice is an device that forms a part of a fuel tank monitoring systemlike that described herein. Additionally or alternatively, the relay maydetermine that a device is compatible if the probe includes anidentifier linked to a fuel provider that services the premises (asopposed to a provider having similar equipment but that does not servicethe premises). The relay may be configured (e.g., upon installation,through input to the relay via a suitable interface, such as via aninterface of the relay or via a wired and/or wireless connection to therelay from a mobile device). Upon determining that a compatible receiveris proximate to the premises, it sends the level of the tank 104 and /or other information and receives confirmation of receipt. Followingconfirmation of receipt, the relay 108 may enter the low power, sleepstate, for a first period of time until conditions for sending are againmet. If the relay 108 cannot establish that a compatible receiver isproximate to the premises, it enters the low power, sleep state, for asecond period of time (which may be the same as or different from, suchas shorter than, the first period of time) before again waking from thelow power, sleep state and listening for the probe signal sent by thevehicle-based mobile computing device 112. The period(s) of time thatthe relay remains in the low power, sleep state may be set by a user oradministrator.

In examples discussed above, including in connection with FIGS. 3A and3B, a monitor transmits fuel tank level data (and, in some embodiments,utilities equipment operating state information) to a relay withoutreceiving a request for data from the relay. Rather, the monitortransmits continuously or upon satisfaction of a condition. In someembodiments, such as the embodiment of FIG. 4B, the relay may insteadquery the monitor for fuel tank level data (and utilities equipmentoperating state information). For example, in some such embodiments, therelay may receive a probe from the device of the vehicle and, inresponse, query the monitor for fuel tank level data. In response toreceiving the query from the relay, the monitor may detect a currentfuel tank level and transmit the fuel tank level to the relay, to besent to the device of the vehicle in response to the probe.

As discussed above, upon receipt of tank level and utilities equipmentoperating state information from the relay for a premises, a refueldetermination facility executing on a device associated with a vehiclemay make a determination of whether a fuel tank of a premises should berefueled in whole or in part. FIG. 5 illustrates an example of a process500 that may be performed by a refuel determination facility executingon the device.

The process 500 begins in block 502, prior to a start of a route for thevehicle. In block 502, the refuel determination facility receives routeand account information for a route that the vehicle is to follow. Theinformation may be received from another computing device associatedwith a fuel delivery service, such as device 114 of FIG. 1. The routeand account information may identify a route that the vehicle is tofollow during a period of time and through an area in which premisesthat are eligible for fuel deliveries are located. The route and accountinformation may further identify the location of each of the accountsalong the route, such as by identifying a street address and/orgeographic location (e.g., latitude, longitude, and/or altitude) foreach premises that has an account with the fuel delivery service and iseligible for a fuel delivery. The account information may also indicate,unique to each account or for all accounts, a threshold fuel level thatwill be used to determine whether to provide fuel to a tank. Bydetermining whether a current fuel level of a tank of a premises is lessthan the threshold fuel level for that premises (or for all premises), adetermination can be made of whether to provide fuel to the tank at thepremises. In some embodiments, the route and account information mayinclude a set of premises for which refueling is scheduled during theroute, which may set the route to be followed. Through the process 500,one or more additional premises to be fueled may be determined. Or, inembodiments in which a refuel determination is not made while thevehicle is proximate to the premises, the vehicle may receive fuel tanklevel information from other premises along a route between premises forwhich refueling are scheduled, and the received tank level informationmay be used to schedule future refuelings for those premises.

Following block 502, the vehicle starts proceeding along the route. Inblock 504, the refuel determination facility monitors for premises withaccounts along the route. The facility may do so by monitoring a currentlocation of the vehicle (e.g., using a location determinationfunctionality) and comparing the current location to locations ofaccounts identified by the route and account information. When thevehicle is proximate to a premises that has an account with the fueldelivery service, the refuel determination facility monitors for atransmission of fuel tank level information, utilities equipmentoperating state information, and premises identifying information from arelay of the premises. (Or, in embodiments like the example of FIG. 4B,transmits (by broadcast or with a targeted transmission) a probe to therelay of the premises requesting transmission of the information.)

In block 506, the facility determines whether fuel tank levelinformation was received. The facility may make the determination bymonitoring for transmissions from relays and determining whether atransmission from a relay includes premises identifying information forthe premises to which the vehicle is proximate.

If no information is received from the relay of a premises, the refueldetermination facility in block 508 outputs an error message to anoperator of the vehicle, indicating that no information was received andthat the vehicle should be positioned proximate to the premises again.The determination that no information was received may be made in anysuitable manner. The facility may operate the device on which it isexecuting to monitor for a transmission while the vehicle is proximateto the premises. The facility may determine that no transmission wasreceived if more than a threshold period of time passes without receiptof a transmission. Additionally or alternatively, if the vehiclecontinues moving while the facility is monitoring for the transmission,the facility may monitor a current location of the vehicle and determinethat no transmission was received when the location indicates that thevehicle is no longer proximate to the premises (e.g., more than athreshold distance away). The error message that is output in block 508may be output via any suitable user interface, as embodiments are notlimited in this respect. For example, a textual message may be output,or a graphical message may be output, a haptic message may be output(e.g., via a vibration of the device), and/or an audible message may beoutput. The error message may instruct the operator of the vehicle tobring the vehicle back to the premises and, accordingly, afteroutputting the error message in block 508, the process 500 returns toblock 504 to monitor for a transmission from the premises.

If, however, the facility determines in block 506 that fuel tank levelinformation and other information was received for the premises, thenthe process 500 continues to block 510. In some embodiments, thefacility may also output a message indicating successful receipt. Themessage may be output via any suitable user interface and may be atextual, graphical, haptic, and/or audible message. In block 510, thefacility evaluates utilities premises operating state information todetermine whether the information is indicative of a problem at thepremises. In the example of FIG. 5, the utilities equipment operatingstate information includes temperature information. The facility mayevaluate temperature information in any suitable manner to determinewhether the temperature is indicative of an error in utilities equipment(e.g., a malfunctioning furnace or other heating equipment). Forexample, the temperature may be compared to a minimum temperature forthe premises or for all premises indicated by the route and accountinformation to determine whether the temperature of the premises isbelow the minimum temperature. If so, the facility may conclude there isa problem and, in response, alert the operator of the vehicle in block512. Specifically, in block 512, the facility may output a messageindicative of the problem at the facility. The message that is outputmay be a textual, graphical, haptic, and/or audible message. Followingoutput of the message, the process 500 continues to block 518, discussedbelow.

If it is determined in block 510 that the utilities equipment operatingstate information does not indicate an error, then the process 500continues to block 514, in which the facility determines whether thefuel level of the tank as indicated by the information received from therelay for the premises meets some condition for fuel to be delivered. Inthe example of FIG. 5, the condition is that the fuel tank level isbelow a minimum level for the premises or for all premises, as indicatedby the route and account information discussed above. However,embodiments are not limited to operating with any particular conditionfor fuel delivery and any suitable condition may be used. If thefacility determines based on the information received from the premisesthat the condition is met, in block 516 the facility outputs a messageto an operator of the vehicle that fuel should be delivered to the tank.The message that is output may be textual, graphical, haptic, and/oraudible.

If, however, it is determined in block 514 that the fuel tank levelinformation received from the premises does not satisfy the condition,then the process 500 continues to block 518.

In block 518, the refuel determination facility determines whether thereare more premises along the route that are to be evaluated. If so, thenthe process 500 continues to block 504, in which the facility monitorsfor a next premises. If, however, there are no more premises along theroute, the process 500 ends.

Techniques operating according to the principles described herein may beimplemented in any suitable manner. Included in the discussion above area series of flow charts showing the steps and acts of various processesthat enable a dynamic determination to be made, at a premises, ofwhether to supply fuel to a tank of a premises. The processing anddecision blocks of the flow charts above represent steps and acts thatmay be included in algorithms that carry out these various processes.Algorithms derived from these processes may be implemented as softwareintegrated with and directing the operation of one or more single- ormulti-purpose processors, may be implemented as functionally-equivalentcircuits such as a Digital Signal Processing (DSP) circuit or anApplication-Specific Integrated Circuit (ASIC), or may be implemented inany other suitable manner. It should be appreciated that the flow chartsincluded herein do not depict the syntax or operation of any particularcircuit or of any particular programming language or type of programminglanguage. Rather, the flow charts illustrate the functional informationone skilled in the art may use to fabricate circuits or to implementcomputer software algorithms to perform the processing of a particularapparatus carrying out the types of techniques described herein. Itshould also be appreciated that, unless otherwise indicated herein, theparticular sequence of steps and/or acts described in each flow chart ismerely illustrative of the algorithms that may be implemented and can bevaried in implementations and embodiments of the principles describedherein.

Accordingly, in some embodiments, the techniques described herein may beembodied in computer-executable instructions implemented as software,including as application software, system software, firmware,middleware, embedded code, or any other suitable type of computer code.Such computer-executable instructions may be written using any of anumber of suitable programming languages and/or programming or scriptingtools, and also may be compiled as executable machine language code orintermediate code that is executed on a framework or virtual machine.

When techniques described herein are embodied as computer-executableinstructions, these computer-executable instructions may be implementedin any suitable manner, including as a number of functional facilities,each providing one or more operations to complete execution ofalgorithms operating according to these techniques. A “functionalfacility,” however instantiated, is a structural component of a computersystem that, when integrated with and executed by one or more computers,causes the one or more computers to perform a specific operational role.A functional facility may be a portion of or an entire software element.For example, a functional facility may be implemented as a function of aprocess, or as a discrete process, or as any other suitable unit ofprocessing. If techniques described herein are implemented as multiplefunctional facilities, each functional facility may be implemented inits own way; all need not be implemented the same way. Additionally,these functional facilities may be executed in parallel and/or serially,as appropriate, and may pass information between one another using ashared memory on the computer(s) on which they are executing, using amessage passing protocol, or in any other suitable way.

Generally, functional facilities include routines, programs, objects,components, data structures, etc. that perform particular tasks orimplement particular abstract data types. Typically, the functionalityof the functional facilities may be combined or distributed as desiredin the systems in which they operate. In some implementations, one ormore functional facilities carrying out techniques herein may togetherform a complete software package. These functional facilities may, inalternative embodiments, be adapted to interact with other, unrelatedfunctional facilities and/or processes, to implement a software programapplication.

Some exemplary functional facilities have been described herein forcarrying out one or more tasks. It should be appreciated, though, thatthe functional facilities and division of tasks described is merelyillustrative of the type of functional facilities that may implement theexemplary techniques described herein, and that embodiments are notlimited to being implemented in any specific number, division, or typeof functional facilities. In some implementations, all functionality maybe implemented in a single functional facility. It should also beappreciated that, in some implementations, some of the functionalfacilities described herein may be implemented together with orseparately from others (i.e., as a single unit or separate units), orsome of these functional facilities may not be implemented.

Computer-executable instructions implementing the techniques describedherein (when implemented as one or more functional facilities or in anyother manner) may, in some embodiments, be encoded on one or morecomputer-readable media to provide functionality to the media.Computer-readable media include magnetic media such as a hard diskdrive, optical media such as a Compact Disk (CD) or a Digital VersatileDisk (DVD), a persistent or non-persistent solid-state memory (e.g.,Flash memory, Magnetic RAM, etc.), or any other suitable storage media.Such a computer-readable medium may be implemented in any suitablemanner, including as computer-readable storage media 606 of FIG. 6described below (i.e., as a portion of a computing device 600) or as astand-alone, separate storage medium. As used herein, “computer-readablemedia” (also called “computer-readable storage media”) refers totangible storage media. Tangible storage media are non-transitory andhave at least one physical, structural component. In a“computer-readable medium,” as used herein, at least one physical,structural component has at least one physical property that may bealtered in some way during a process of creating the medium withembedded information, a process of recording information thereon, or anyother process of encoding the medium with information. For example, amagnetization state of a portion of a physical structure of acomputer-readable medium may be altered during a recording process.

In some, but not all, implementations in which the techniques may beembodied as computer-executable instructions, these instructions may beexecuted on one or more suitable computing device(s) operating in anysuitable computer system, including the exemplary computer system ofFIG. 1, or one or more computing devices (or one or more processors ofone or more computing devices) may be programmed to execute thecomputer-executable instructions. A computing device or processor may beprogrammed to execute instructions when the instructions are stored in amanner accessible to the computing device or processor, such as in adata store (e.g., an on-chip cache or instruction register, acomputer-readable storage medium accessible via a bus, etc.).

Functional facilities comprising these computer-executable instructionsmay be integrated with and direct the operation of a singlemulti-purpose programmable digital computing device, a coordinatedsystem of two or more multi-purpose computing device sharing processingpower and jointly carrying out the techniques described herein, a singlecomputing device or coordinated system of computing device (co-locatedor geographically distributed) dedicated to executing the techniquesdescribed herein, one or more Field-Programmable Gate Arrays (FPGAs) forcarrying out the techniques described herein, or any other suitablesystem.

FIG. 6 illustrates one exemplary implementation of a computing device inthe form of a computing device 600 that may be used in a systemimplementing techniques described herein, although others are possible.It should be appreciated that FIG. 6 is intended neither to be adepiction of necessary components for a computing device to operate as adevice associated with a vehicle in accordance with the principlesdescribed herein, nor a comprehensive depiction.

Computing device 600 may comprise at least one processor 602, a networkadapter 604, and computer-readable storage media 606. Computing device600 may be, for example, a desktop or laptop personal computer, apersonal digital assistant (PDA), a smart mobile phone, or any othersuitable computing device. Network adapter 604 may be any suitablehardware and/or software to enable the computing device 600 tocommunicate wired and/or wirelessly with any other suitable computingdevice over any suitable computing network. The computing network mayinclude wireless access points, switches, routers, gateways, and/orother networking equipment as well as any suitable wired and/or wirelesscommunication medium or media for exchanging data between two or morecomputers, including the Internet. Computer-readable media 606 may beadapted to store data to be processed and/or instructions to be executedby processor 602. Processor 602 enables processing of data and executionof instructions. The data and instructions may be stored on thecomputer-readable storage media 606 and may, for example, enablecommunication between components of the computing device 600.

The data and instructions stored on computer-readable storage media 606may comprise computer-executable instructions implementing techniqueswhich operate according to the principles described herein. In theexample of FIG. 6, computer-readable storage media 606 storescomputer-executable instructions implementing various facilities andstoring various information as described above. Computer-readablestorage media 606 may store a refuel determination facility 608, whichmay implement some of the techniques described above. The storage media606 may additionally store route information 610, which may identify aroute that is to be followed by a vehicle to visit premises that areeligible for refueling. Account information 612 may also be stored bythe storage media 606, which may include information identifyingpremises by location and account number, and identifying any othersuitable information about an account such as information to be used indetermining whether a refueling condition is met (e.g., a tank level) orwhether utilities equipment is properly functioning (e.g., a minimumtemperature).

While not illustrated in FIG. 6, a computing device may additionallyhave one or more components and peripherals, including input and outputdevices. These devices can be used, among other things, to present auser interface. Examples of output devices that can be used to provide auser interface include printers or display screens for visualpresentation of output and speakers or other sound generating devicesfor audible presentation of output. Examples of input devices that canbe used for a user interface include keyboards, and pointing devices,such as mice, touch pads, and digitizing tablets. As another example, acomputing device may receive input information through speechrecognition or in other audible format.

Embodiments have been described where the techniques are implemented incircuitry and/or computer-executable instructions. It should beappreciated that some embodiments may be in the form of a method, ofwhich at least one example has been provided. The acts performed as partof the method may be ordered in any suitable way. Accordingly,embodiments may be constructed in which acts are performed in an orderdifferent than illustrated, which may include performing some actssimultaneously, even though shown as sequential acts in illustrativeembodiments.

Various aspects of the embodiments described above may be used alone, incombination, or in a variety of arrangements not specifically discussedin the embodiments described in the foregoing and is therefore notlimited in its application to the details and arrangement of componentsset forth in the foregoing description or illustrated in the drawings.For example, aspects described in one embodiment may be combined in anymanner with aspects described in other embodiments.

Use of ordinal terms such as “first,” “second,” “third,” etc., in theclaims to modify a claim element does not by itself connote anypriority, precedence, or order of one claim element over another or thetemporal order in which acts of a method are performed, but are usedmerely as labels to distinguish one claim element having a certain namefrom another element having a same name (but for use of the ordinalterm) to distinguish the claim elements.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” “having,” “containing,” “involving,” andvariations thereof herein, is meant to encompass the items listedthereafter and equivalents thereof as well as additional items.

The word “exemplary” is used herein to mean serving as an example,instance, or illustration. Any embodiment, implementation, process,feature, etc. described herein as exemplary should therefore beunderstood to be an illustrative example and should not be understood tobe a preferred or advantageous example unless otherwise indicated.

Having thus described several aspects of at least one embodiment, it isto be appreciated that various alterations, modifications, andimprovements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis disclosure, and are intended to be within the spirit and scope ofthe principles described herein. Accordingly, the foregoing descriptionand drawings are by way of example only.

What is claimed is:
 1. A system to determine a level of fuel in a fueltank at a premises, the apparatus comprising: a pair of electricallyisolated conductive elements suspended inside the fuel tank at a fixeddistance from each another, each of the pair of electrically isolatedconductive elements comprising: a proximal end positioned above ahighest level of fuel in the fuel tank, and a distal end opposite theproximal end positioned a distance from a bottom surface of the fueltank; an electrical circuit that includes the pair of electricallyisolated conductive elements, the pair of electrically isolatedconductive elements forming a capacitor in the electrical circuit; and acontrol circuit configured to calculate, based on capacitor responsedata determined by the electrical circuit, the level of fuel in the fueltank.
 2. The system of claim 1, wherein the electrical circuit furthercomprises a resistor.
 3. The system of claim 1, wherein the electricalcircuit is arranged to output capacitor response data including aplurality of points, each point comprising a time and voltage of thecapacitor at the time.
 4. The system of claim 1, wherein the controlcircuit is configured to receive the capacitor response data responsiveto application of an electrical voltage to the electrical circuit. 5.The system of claim 1, wherein: the control circuit comprises at leastone processor that is a component of a computing device disposed remotefrom the premises; and the at least one processor is configured toreceive the capacitor response data via one or more networks.
 6. Thesystem of claim 5, wherein: the at least one processor is configured toreceive the capacitor response data together with an identifier for thesystem and/or the premises; and the computing device retrievesdimensions of the fuel tank from a dataset containing the dimensions,based at least in part on the identifier, and calculates the level offuel based at least in part on the capacitor response data and thedimensions of the fuel tank.
 7. The system of claim 1, wherein: thecontrol circuit is configured to calculate the level of fuel in the tankby calculating a volume of fuel remaining in the tank.
 8. The system ofclaim 7, wherein the control circuit is configured to calculate thevolume of fuel by calculating, based on the capacitance, a ratio of acurrent fuel height to a maximum fuel height in the tank.
 9. The systemof claim 8, wherein the control circuit is configured to calculate theratio based at least in part on a time constant for the electricalcircuit determined based at least in part on the capacitor responsedata, a first known time constant for the electrical circuitcorresponding to the tank at full fuel capacity, and a second known timeconstant for the electrical circuit corresponding to the tank empty offuel.
 10. The system of claim 1, wherein the electrical circuitcomprises a timer chip and at least one of the pair of electricallyisolated conductive elements connected to a threshold input of the timerchip.
 11. A method comprising: determining a level of fuel in a tankusing a pair of electrically isolated conductive elements disposedwithin the tank at a fixed distance from each other, wherein determiningthe level of fuel in the tank comprises: exciting an electrical circuitthat includes the pair of electrically isolated conductive elementsacting as a capacitor; determining capacitor response data for theelectrical circuit; and calculating, based on the capacitor responsedata, the level of fuel in the fuel tank.
 12. The method of claim 11,wherein each of the pair of electrically isolated conductive elements isdisposed within the tank with a proximal end positioned above a highestlevel of fuel in the fuel tank and a distal end opposite the proximalend positioned a distance from a bottom surface of the fuel tank. 13.The method of claim 11, wherein determining the capacitor response datacomprises determining capacitor response data including a plurality ofpoints, each point comprising a time and voltage of the capacitor at thetime.
 14. The method of claim 11, wherein calculating the level of fuelin the tank comprises calculating a volume of fuel remaining in thetank.
 15. The method of claim 14, wherein calculating the volume of fuelcomprises calculating, based on the capacitance, a ratio of a currentfuel height to a maximum fuel height in the tank.
 16. The method ofclaim 15, wherein calculating the ratio comprises calculating based atleast in part on a time constant for the electrical circuit determinedbased at least in part on the capacitor response data, a first knowntime constant for the electrical circuit corresponding to the tank atfull fuel capacity, and a second known time constant for the electricalcircuit corresponding to the tank empty of fuel.
 17. The method of claim12, wherein the electrical circuit comprises a timer chip and at leastone of the pair of electrically isolated conductive elements areconnected to a threshold input of the timer chip.
 18. At least onecomputer-readable storage medium having encoded thereon executableinstructions that, when executed by at least one processor, cause the atleast one processor to carry out a method comprising: determining alevel of fuel in a tank using a pair of electrically isolated conductiveelements disposed within the tank at a fixed distance from each other,wherein determining the level of fuel in the tank comprises: exciting anelectrical circuit that includes the pair of electrically isolatedconductive elements acting as a capacitor; determining capacitorresponse data for the electrical circuit; and calculating, based on thecapacitor response data, the level of fuel in the fuel tank.
 19. The atleast one computer-readable storage medium of claim 18, wherein each ofthe pair of electrically isolated conductive elements is disposed withinthe tank with a proximal end positioned above a highest level of fuel inthe fuel tank and a distal end opposite the proximal end positioned adistance from a bottom surface of the fuel tank.
 20. The at least onecomputer-readable storage medium of claim 18, wherein calculating thelevel of fuel in the tank comprises calculating a volume of fuelremaining in the tank.